Hey everyone! Here's my latest bit of fun. So, '87 TR. Cold. Start it up. Idles for about 5-10 mins. Coolant temp in the middle between 140 and 190 (ie, cooling fans are definitely not on yet). Then I hear an audible "tink" as if some system is turning on or off and then the idle starts missing and becomes uneven. Cooling fans are still definitely not on. I can capture this on video if it helps. If it were an old 60s car with carburetion, I'd think it was something to do with the choke opening up and the mixture becoming too lean. Before I go that path though, just thought I'd ask if anyone knows what system the "tink" is involved with? Thanks!
Has there ever been an adjustment to the Throttle Position at idle? Could be that the bypass valve is doing its job to maintain idle until the engine temp closes it. That's the tick you hear and the engine resorts to the maladjusted idle position. Just a thought Image Unavailable, Please Login
It's weird; it's not like the idle is set too low. It's like it surges between like 800 - 1000 RPM, and I think I hear the 'thud' of non-firing cylinders every now and then. I'll post a video later today. And it all happens after that "tink".
how high are the rpm during running when cold and until it makes "tink" ? you checked the 2 auxiliary air valves? those are responsible for higher rpm when cold. inside there is a "plate" opening (when cold ) and closing ( when warm ) a bypass. may be this plate makes "tink" when it closes completely? but that would not be normal
Just idling, say, 900 RPM? I haven't pressed gas pedal since starting it up. Where are the aux air valves located?
(Assuming that you have a US version TR) The "tink" is caused by the coolant thermoswitch on the "Y" water fitting going from cold (closed) to open (warm) -- which turns off the air injection air pump clutch (that's probably the "tink" that you hear), but it also takes the KE-Jet injection system from running open-loop (stupid) to closed-loop (relying on the O2 sensor outputs). The first diagnostic test you should try IMO is just unplugging the single wire from each O2 sensor just after the "tink" occurs, and see if the idle running goes back to OKish (unplugging the O2 sensors forces the system back to open-loop operation -- but don't get them mixed up -- mark them before disconnecting them to keep track of who's who). If it does restore a good warm idle, then it gets more complicated to continue...
when the engine is really cold then the 1100 rpm are not unusual, even a little to high, but when warm it should be between 800 and 900. so that what I thaught first is ok ( bypass vacuum valve ) the aux air valve you see in the picture directly in front of the elbow from the trottle, left and right a hose on it and hard to see if you don´t know an electrical connection right side under the hose. but as steve has written because of the US airpump we don´t have here in EU I also think that this problem has soemthing to do with problem.
Hey everyone, I made 2 videos, for reference. The first one is what happens now - both O2 sensors connected. I added snazzy captions to point different things out (ooh, so advanced! ). The video quality is crappy but the audio quality is what matters. http://www.ecartdeluxe.com/crapidle.mp4 The second one is with both O2 sensors disconnected, per Steve. The second video takes place immediately after stopping and restarting the engine (and disconnecting the sensors when the car is off). And lo and behold, the idle is back to is regular steady state! So now I'm assuming it gets more complicated as Steve mentions. http://www.ecartdeluxe.com/BOTHO2SENSORSDISCONNECTED.mp4 Interestingly enough, I connected the O2 sensors one at a time, and on one of them, the idle was still fine, but on the other, it was crap! This coincides with one of my remarks in the first video about the exhaust sounding worse on the passenger side, no? Oh, and when the O2 sensors were disconnected I took the TR for a drive and WHAT A DIFFERENCE (in a good way!) Throttle response aplenty, runs much more even. I think I might just leave them disconnected at this rate! So, where to next?
This depends on what type of muffler that you have on the car -- some (e.g., Tubi) keep the exhaust streams completely separated, so there is a correlation between which tailpipe to which bank. The stock US TR muffler mixes the exhaust streams so not such a direct relationship. Yes, hugely! The next thing to look into (based on your reported results) is if there is an air leak into the exhaust stream upstream of the O2 sensor on the bank that give the bad warm idle with the O2 sensor plugged in (bad gasket joint, broken off sampling tubes, bad air injection cut-off valve). The easiest functional way to do this is to measure the voltage on the single wire (relative to ground) from the O2 sensor on the "bad" bank -- the proper result at idle would be: 1. Immediately after cold start-up = meaningless (because an O2 sensor output is only valid when the sensor element is relatively hot) 2. With coolant temp between ~140 deg on the coolant gauge but below the "tink" point = low voltage ~.1V DC (lean) because the air injection pump is adding extra air into the exhaust stream). 3. Above the "tink" point with the O2 sensor unplugged = ~.8V DC (just slightly rich above stoichiometric). If this still measures low (like less than 0.5V) = could be sign of unwanted air getting into the exhaust stream. Or it could be a sign that the bank's mixture is just set too lean, but you report the unplugged idle condition is good so that indicates the bank's mixture is set OK-to-rich. 4. Above the "tink" point with the O2 sensor plugged in = voltage should be "wandering" between the lean boundary (0.1~0.2V DC) and the rich boundary (0.8~0.9V DC) every couple of seconds. If you can report on #3 and #4 results for both banks (as looking at how a good bank is running can be a useful comparison ), that might give a clue for where to go next. Another possibility is that your "bad" bank fuel distributor is not delivering equal amounts of fuel to all 6 cylinders. Setting the mixture rich and unplugging the O2 sensor can mask this condition (and a lot of F seem to wind up here), but it's not so great -- especially if you have active precats/cats as this will cause them to run hotter/overheat. Another possibility is you have a bad O2 sensor so you might try swapping them (which requires swapping their physical positions and the single wire connections - the 2-pin connections are not bank specific) or bench-testing the "bad" one as described online.
Excellent, thanks for the help again Steve! I'll check that stuff tonight. And yes I have Tubi exhaust And Jaguar15, the AC wasn't turned on at the time. Would it still recycle?
Steve, I have to ask but you don't have to answer. What do you do that you know so much about these things?
I own a TR, drive it regularly, and have to fix it when it breaks Seriously -- I don't make mini-documentaries about the projects that I've had to hassle with like some of the FChatters, but, almost always, when I post on something -- BTDTGTTS...
When Steve talks, all TR owners should listen and take notes. I do. His helpful hints and troubleshooting skills are GOLD. Thanks Steve!
Mr. Magnusson, I don't know you sir, but, I would have to rank you as the # 1 person here on TR's. You know and understand the minute details, tolerances, ft-lbs, and voltages which show you have earned your badges as you have BTDTGTTS.... No disrespect for the other great people here. PS, I forgot, nix the AC recycle idea if it is off.
also from me THANKs to steve as he helped me out just last 2 weeks with a problem with the TR. but what pls means: BTDTGTTS B: big T: thanks D: daily T: to G: ? T: ? T: ? S: ?
Been There, Done That, Got The T-Shirt (it's English slang for sarcastically saying that you are intimately familiar with something -- usually something not pleasant...)
OK, the results are in! Hopefully the row spacing holds. Oh also, I replaced my two O2 sensors in Feb of this year as part of my problems with emissions (I believe I posted about it here, in fact!) Anyway, here are the results.... Test. _ Driver side. _ Passenger side Startup. _ 1.1. _ 1.1 Warm, before tink. _ .2 - .3. _ .3 Post tink, O2 unplug. _ .9 - .94. _ 1.05 Post tink, O2 plugged in _ .2 - .8. _ 1 - <.1 That last measurement was the most concerning. My voltmeter would get in to millivolts as part of its autoscale. I tested it many times to make sure I wasn't missing something (even got it on video too). What are your thoughts?
In summary, the last measurement of the passenger side O2 sensor ranged from 1 volt to less than .1 volts! Sent from my Nexus 10 using Tapatalk
